Aim

To explore the physics and technology of novel approaches to optical localization measurements – of the static position and/or dynamic motion of nano-objects – with deeply sub-wavelength precision, leveraging a combination of topologically structured light fields and artificial intelligence.

Details

Despite the tremendous recent progress in super-resolution optical imaging and metrology, a huge gap remains between optical techniques and the atomic scale of resolution accessible in electron microscopy. Our work is showing that localization precision surpassing the diffraction limit of conventional microscopy thousands of times over is possible. The techniques being developed may be applied in a range of systems to enable non-invasive study of motion induced by ambient forces and fields, or thermal motion.
We have shown that the position of a nanowire can be localized with precision better than 100 pm (λ/5300), in single-shot measurements insensitive to ambient (instrumental) noise, via deep learning analysis of topologically structured light scattering.

Our work has revealed the mechanisms by which phase singularities in topologically structured light fields can enable orders-of-magnitude sensitivity improvements such measurements; and shown how this advantage can be extended to retrieval of dimensional parameters from arbitrarily structured objects.

In ongoing work, we are exploring the practical and fundamental limits on such measurements, e.g. imposed by camera specifications, and the polarization of incident light.

References

[1] T. A. Grant, et al., “Resolving complex subwavelength grating structures using topologically structured light,” Opt. Express 34, 2693 (2026) doi: 10.1364/OE.580365

[2] T. Grant, et al., “Localization of nanoscale objects with light singularities,” Nanophotonics 14, 915 (2025) doi: 10.1515/nanoph-2024-0639

[3] C-H. Chi, et al., “Robust optical picometrology through data diversity,” Opt. Mater. Express 14, 2377 (2024) doi: 10.1364/OME.531665

[4] Y. Wang, et al., “3D positional metrology of a virus-like nanoparticle with topologically structured light,” Appl. Phys. Lett. 124, 221102 (2024) doi: 10.1063/5.0207958

[5] Liu, et al., “Picophotonics – subatomic optical localization beyond thermal fluctuations,” Nat. Mater. (2023). doi: 10.1038/s41563-023-01543-y